Millionaire’s Shortbread Cake is a fantastic riff on its namesake bar. Layers of brown sugar sponge cake are piled full of caramel sauce, chocolate ganache and homemade shortbread. Who wants seconds?
One of my favourite pastimes is dreaming up new cake recipes and working out how to style them. I’ve been toying with the idea of a millionaire’s shortbread cake since the summer. But it was only last week that I finally got around to writing my thoughts down.
This bake manages to combine – in cake form – the 3 essential elements of traditional millionaires shortbread:
- delicate, crisp and buttery shortbread
- smooth as silk caramel
- decadent chocolate
Why be forced to pick between cake and caramel shortbread if you can have it all? That’s my winning theory today, anyway.
What is Millionaire’s Shortbread Cake?
I’ve used a brown sugar sponge as the base for this cake, and incorporated chunks of shortbread cookies, caramel sauce and chocolate ganache into each layer. So the trio of flavours in traditional millionaire’s shortbread all have a starring role to play.
After much deliberation, I plumped for Italian meringue buttercream subtly flavoured with caramel.
Making Italian buttercream is a lengthier process than whipping up a batch of regular buttercream. But the ultra silky smooth texture is worth the extra effort. It really does compliment the very notion of caramel in this cake.
Italian buttercream is less sweet than regular buttercream and so works in perfect harmony with the caramel and chocolate sauces without turning the cake into an oppressively sweet affair.
Finally, I decided to turn this caramel shortbread cake into a drip cake. Partly to give it a striking & impressive look but also because it’s a surefire way to ensure that a good portion of caramel sauce accompanies each slice.
This millionaire’s caramel cake is rather dapper in the looks department and a total joy to eat.
Within each layer a gently hit of caramel and chocolate flavour bursts through along with a satisfying buttery crunch from the shortbread cookies. To top it all, the buttercream is out of this world tasty and smooth as silk.
Why Use Brown Sugar in Cakes
Using brown sugar in place of regular white sugar adds an extra depth of flavour to a cake.
Brown sugar imparts a subtle, but wonderful, hint of caramel to a sponge cake and yields a slightly darker colour.
These qualities are not always suitable. But the substitution works like a charm for this millionaire’s shortbread cake, where the aim of the game is to create a rich, buttery and flavour forward cake to work in harmony with the caramel and chocolate elements.
Tips for Making This Millionaire’s Cake
- My top tip that must be adhered to for this millionaire’s cake is to use proper butter in the sponge cake. Since we are trying to replicate the rich & buttery taste of shortbread in the cake, using a butter substitute, such as baking margarine will not do. Butter is essential to produce a rich & indulgent crumb
- Prior to mixing, ensure that the brown sugar has not solidified into lumps. If it has, these lumps need to be removed before baking can begin. Either crush the sugar with a spoon, rub it between fingers or pulse through a food processor
- Make the caramel sauce well ahead of time – preferably the day before – and store at room temperature until ready to use. Check it has cooled to around 20C/ 68F before attempting to drizzle over the cake and do not pour warm sauce onto the cake as it will melt the buttercream
- Make the chocolate sauce around 1 hour before using it. Again, ensure it is room temperature before using on the cake. Similarly, if used when warm the sauce will ruin the buttercream
- If either the caramel sauce or chocolate sauce has thickened too much to drizzle, heat gently in the micowave in 5 second bursts until it is just loose enough to drizzle
- If making this cake on a very hot day, please be aware that the caramel and chocolate sauce may be looser than intended. The cake will still turn out delicious, but it may be harder to achieve a neat finish when decorating
- Whilst all of the components of this millionaire’s cake can be made ahead of time, I recommend assembling the cake on the day you intend to serve it. The shortbread will soften once exposed to air/ buttercream, so this cake is best eaten quickly
- If eaten within 24 hours, there is no need to store this cake in the fridge
How to Decorate a Drip Cake
My main concern, when decorating this caramel shortbread cake, was the caramel sauce bleeding too far into the centre of the cake, and interfering with the chocolate ganache.
I wanted neat sections of both, so here is what I did:
- I piped a thin circle (approx 1/2 cm) of buttercream around the top of the cake – about 1 1/2 cm from the edge. This acted as a barrier between the caramel and chocolate sections
- I squeezed my caramel sauce around the edge of the cake, ensuring it flowed to the rim of the buttercream barrier and started to drip down the sides of the cake. I used a squeezy bottle to do this, but a piping bag will work just as well
- Next, I spooned the chocolate ganache into the centre of the cake and used a small palette knife to ensure it reached the buttercream rim
- Finally, I piped over the buttercream circle using a fancy nozzle to hide my makeshift barrier
Although these steps are straightforward, the result is definitely impressive. Give it a go yourself if you haven’t attempted a drip cake before (this was my first one) and don’t’ forget to tag #jane_littlesugarsnaps on Instagram so I can see how you got on.
Find my other fancy layers cakes:
- Triple Chocolate Layer Cake
- Turkish Delight Cake
- Mint Choc Chip Cake
- Triple Coffee Cake
- White Chocolate & Peppermint Cake
Millionaire’s Shortbread Cake
- 3 x 6 inch cake tins
For the Caramel Sauce
- 100 g Caster sugar
- 30 g Butter
- 90 ml Double (heavy) cream
- 1/8 tsp Salt
For the Shortbread
- 30 g Butter
- 30 g Plain (all purpose) flour
- 15 g Cornflour (cornstarch)
- 15 g Caster sugar
- Pinch salt
For the Chocolate Ganache Sauce
- 30 g Chocolate see notes
- 45 ml Double (heavy) cream
For the Cake
- 180 g Butter – softened
- 180 g Light brown sugar
- 180 g Plain (all purpose) flour
- 1 1/2 tsp Baking powder
- 3 Eggs – large, free range
- 3 tbsp Milk (whole/ full fat)
- 1 tsp Vanilla extract
For the Italian Meringue Buttercream
- 3 Egg white (large, free range)
- 1/8 tsp Cream of tartar
- 240 g Caster sugar
- 70 ml Water
- 300 g Butter (softened)
Make the Caramel Sauce
- Make the caramel by putting the caster sugar (in an even layer) in a heavy-based saucepan and let cook over a moderate heat, swirling around the pan a couple of times to cook evenly. The sugar should first melt, then turn a lovely amber colour
- Once the sugar has dissolved and the colour is deep amber, carefully add the butter & cream. Take care as the mixture may bubble up. Don't worry if the caramel solidifies in places. Put the pan back on a gentle heat and cook for around 2 minutes more, stirring frequently until it is smooth. Do not let the caramel boil
- Meanwhile, grind the sea salt in a pestle and mortar
- Take the caramel off the heat and stir in the salt then set aside to cool to room temperature (at least 6 hours, preferably overnight – cover once cool)
Make the Shortbread
- Preheat the oven to 150C/ 300F/ Gm2 and line a baking sheet with parchment paper
- Put the flours, sugar & salt into a bowl & stir briefly
- Cube the butter, add to the bowl and toss
- Next, rub the butter into the dry ingredients. It will at first resemble sand but keep rubbing until the dough begins to bind
- Form into a ball and knead very briefly before rolling out to around 2mm thickness
- Cut small circles out – I used a cutter measuring approx 2 1/2 cm
- Reroll the dough to get a few more circles until you have around 30 shortbread cookies
- Lay the cookies on the parchment at least 1 cm apart, chill for 30 minutes and then bake for 15-20 minutes until beginning to turn golden
- Set aside to cool completely then store in an airtight container until reader to assemble the cake
Make the Chocolate Ganache
- Chop the chocolate finely and place in a small heatproof bowl
- Heat the cream to scalding, but not boiling and pour over the chocolate
- Let sit for 1 minute then stir until smooth
- Set aside to cool
Make the Brown Sugar Sponge Cakes
- Preheat the oven 170C/ 325F/ GM3 and grease & line 3 x 6 inch sandwich cake tins with parchment
- Using electric beaters, beat the butter and sugar together until light and fluffy
- Briefly mix the eggs in a jug and gradually add a tsp at a time into the creamed butter & sugar, beating well in between each addition (adding the egg really slowly reduces the risk of the mix splitting)
- Add the vanilla extract and milk, then beat again
- Sift the flour and baking powder into the bowl and gently & briefly fold in half using a large metal spoon (about 8 turns of the spoon). Add the rest of the flour and continue to fold in until all ingredients are throughly combined. Take care not to overwork the batter though
- Divide between the baking tins and bake for approximately 20-23 minutes
- Test that the cakes are baked through by poking a cocktail stick into them – if it comes out clean then the cakes are ready. If not, return to the oven for a couple more minutes, then test again
- Once out of the oven remove from the baking tins and allow to cool completely on a wire rack
Make the Italian Meringue Buttercream
- Put 200g sugar and the water into a medium saucepan then place on medium-low heat and cook until the sugar dissolves. Keep the syrup on a low heat while you prepare the egg whites, then, when the meringue reaches the soft peak stage, raise the heat and cook until the syrup reaches a temperature of 115C (240F)
- Beat the egg whites and cream of tartar in the bowl of a stand mixer. Add the remaining 40g of sugar spoonful by spoonful and then keep beating until soft peaks form.
- When the temperature of the sugar syrup reaches 110C (230F) beat the meringue on high until the stiff peak stage
- Once the syrup reaches 115C (240F) drizzle it slowly into the stiff egg whites whilst the mixer is still running. Take care to pour the syrup into the side of the bowl directly onto the meringue and not onto the metal whisk (to avoid the risk of the incredibly hot syrup splattering you)
- Continue to whip the meringue until it is lukewarm
- Switch to a paddle attachment. Add room temperature butter into the running mixer one tablespoon piece at a time then add 60ml of the caramel sauce (cold) to the buttercream
- Beat until everything is combined and the mixture has reached a silky consistency
Assemble the cake
- Place 1 layer of cake on a plate/ stand and pipe buttercream over it
- Drizzle 1 tbsp caramel sauce and 1 tbsp chocolate ganache over the buttercream. break up 5 shortbread cookies into pieces and scatter over the top
- Place another layer of sponge on top and repeat
- Top with the final layer of sponge cake
- Use some icing to cover the top and side of the cake – a naked cake looks wonderful here
- Pipe a thin circle of buttercream onto the top of the cake about 1 1/2 cm in from the edge. This will act as a barrier and prevent the caramel and chocolate running into each other
- Drizzle caramel sauce around the edge of the cake, ensuring that it reaches the buttercream barrier and begins to drip down the side of the cake. Use either a squeezy bottle or a piping bag and nozzle to achieve this
- Fill the centre section with chocolate ganache and use a small palette knife to spread it to the barrier. Do not overfill the centre with ganache, otherwise, it will flood over the buttercream barrier
- Pipe buttercream rosettes over the top to hide the buttercream barrier and top each rosette with a shortbread cookie
- Best served on the day it is assembled. Can keep for up to 3 days but expect the shortbread to soften and loose its crunchy texture